CH. xxm THE HAWAIIAN MOUNTAIN- FLORA 269 



this sense they may be regarded as cut off from the regions 

 around. In Fiji and Tahiti only about a fourth are in this 

 manner isolated, the agencies of dispersal being still effective with 

 the majority of the genera. It is apparent, therefore, that the 

 same question concerning the cause of the failure of the means 

 of dispersal presents itself in this era as in the last, and most 

 markedly in the instance of Hawaii. 



The simplest and quickest plan for bringing into relief the 

 prominent features of this age is first to regard the genera from 

 the standpoint of the elevation of their stations. We have before 

 remarked that in the occurrence of extensive regions of great 

 altitude the Hawaiian Islands differ conspicuously from the groups 

 of Tahiti and Fiji (and I may add Samoa) ; and that they present 

 conditions for the development of a temperate mountain-flora that 

 are not found at all in Fiji and are barely represented in Tahiti. 

 That the Hawaiian flora responds to this contrast between the 

 elevations of the three groups is well established ; and I will now 

 proceed to refer more in detail to the subject. 



THE MOUNTAIN-FLORAS OF THE PACIFIC ISLANDS. 



In the Hawaiian Islands there are at least 37 or 38 genera, 

 making up about 19 or 20 per cent, of those belonging to this era, 

 that may be designated mountain genera, nearly all of them being 

 characterised as appertaining exclusively or in the main to 

 temperate regions, or as frequenting mountain-tops in tropical 

 latitudes. In Tahiti there are only 7 or 8 of such genera, about 

 4 per cent, of the total for the era. In Fiji, excluding the Conifers, 

 there are only 4 or 5, or not 2 per cent, of the whole. In Samoa, 

 which may be included in the Fijian area, there are 3, or about 2 

 per cent, of the total. These are results which we might have 

 expected from the varying altitudes of these groups, as described 

 in Chapter XIX. 



Few things give more pleasure to the botanist than his 

 recognition in some remote locality of plants long familiar to him 

 in other regions. This will often be his lot on the mountain 

 summits of Hawaii. If he has been a mountain-climber in many 

 countries, he will there notice again the genera Artemisia, 

 Geranium, Plantago, Ranunculus, Rubus, Sanicula, Vaccinium, 

 and others that he has met perhaps either in the Rocky Mountains 

 or in the Andes or in Equatorial Africa or in the Himalayas. If 

 fresh from Chile he will find on these heights the familiar Gunnera 



